Grinding wheel dressing apparatus

ABSTRACT

A wheel dressing apparatus for dressing the periphery of a grinding wheel with a cutter mounted for following the straight and curved periphery of the grinding wheel. One cam is included for cross-feeding the cutter transversely of the periphery of the grinding wheel and a second cam produces pivoting movement of the cutter along a curved path having a component directed radially of the grinding wheel. The second cam also maintains the cutter normal to the periphery of the grinding wheel as it is pivoting.

United States Patent [191 Hoglund GRINDING WHEEL DRESSING APPARATUS [75] Inventor: Nils O. Hoglund, Short Hills, NJ.

[73] Assignee: Hoglund Engineering and Manufacturing Company, Inc., Berkeley Heights, NJ.

[22] Filed: Feb. 28, 1972 [21] Appl. No.: 230,024

[52] U.S. Cl 125/11 PH, 125/11 A, 125/11 BS [51] Int. Cl B24b 53/08 [58] Field of Search 125/11 R, 11 CC, 11 BS, 125/11 A, 11 TP, 11 PH [56] References Cited UNITED STATES PATENTS 2,936,750 5/1960 Hoglund l25/ll TP 2,973,755 3/1961 Hoglund l25/ll TP 3,455,289 7/1969 Hoglund 125/ll R [451 Aug. 6, 1974 3,570,468 3/1971 Hoglund l25/ll CC 3,608,537 9/1971 Uhtenwoldt l25/ll A 3,662,73l 5/l972 Kikuchi l25/ll A Primary Examiner0thell M. Simpson Assistant ExaminerNicholas P. Godici Attorney, Agent, or FirmPennie & Edmonds 5 7 ABSTRACT A wheel dressing apparatus for dressing the periphery of a grinding wheel with a cutter mounted for following the straight and curved periphery of the grinding wheel. One cam is included for cross-feeding the cutter transversely of the periphery of the grinding wheel and a second cam produces pivoting movement of the cutter along a curved path having a component'directed radially of the grinding wheel. The second cam also maintains the cutter normal to the periphery of the grinding wheel as it is pivoting.

8 Claims, 9 Drawing Figures BACKGROUND OF THE INVENTION With conventional grinding apparatus using a grinding wheel having a peripheral contour shaped to produce a specific grinding operation, it is necessary that the grinding wheel be dressed periodically. This must be done in order to maintain the desired peripheral contour of the grinding wheel. Wheel dressing apparatus may be mounted directly on the grinding apparatus and means provided for bringing it into operative association with the grinding wheel. With conventional dressing equipment, a diamond cutter is mounted in the dressing apparatus so that it can move along the periphery of the grinding wheel as the latter rotates. With grinding wheels having peripheral contours including straight and curved sections, it is necessary that the diamond cutter be moved both transversely of the grinding wheel; that is, along the axis of the grinding wheel, and radially of the grinding wheel. Also, in order to obtain a precise dressing of the grinding wheel to the exact contour desired, it is necessary to maintain the cutter normal to the peripheral contour of the wheel as it moves across the peripheral surface.

With some types of wheel dressing apparatus, the movement of the diamond cutter across the wheel along both the straight and curved sections is determined either wholly or partially by manually operated controls. In other types of equipment, cams and/or hydraulic mechanisms are used for controlling the movement of the diamond cutter. For example, one cam may be used for effecting transverse movement of the cutter along straight sections of the periphery of the grinding wheel, a second cam for producing radial movement of the cutter along curved sections, and a third cam for causing pivoting movement of the cutter as it is moved radially to maintain the cutter normal to the surface being dressed. Some or all of these movements may be hand controlled. Examples of wheel dressing apparatus of the types described above are disclosed in my prior US. Pat. Nos. 2,596,555, 2,658,498, 2,902,025, and 2,973,755.

SUMMARY OF THE INVENTION The present invention relates to a wheel dressing apparatus of simplified construction wherein the transverse radial and pivoting movements of the diamond cutter are controlled by a single reciprocating cam slide having two cams, one for effecting cross-feeding of the cutter transversely of the grinding wheel and another for effecting pivoting of the cutter along the curved section of the grinding wheel. Structurally, the wheel dressing apparatus includes a first fixed support, a second support, carrying the diamond cutter, mounted on the first support for movement transversely of the periphery of the grinding wheel, means for rotating the cutter on the second support, and the above-mentioned cam slide and cam means for controlling the movement of the cutter across the grinding wheel. Hydraulic means is provided for effecting reciprocation of the cam slide and it comprises the sole source of the power required for moving the cutter along the periphery of the grinding wheel.

BRIEF DESCRIPTION OF THE DRAWING FIG. 1 is a cross-sectional view of the wheel dressing apparatus of the present invention shown associated with a grinding wheel;

FIG. 2 is a cross-sectional view taken along lines 22 of FIG. 1;

FIG. 3 is an end view, partially in cross section, of the apparatus shown in FIG. 1; and

FIGS. 49 are views showing different cam-cam follower arrangements which may be used in the apparatus of FIG. 1 for producing contours of the different shapes.

DESCRIPTION OF THE PREFERRED EMBODIMENT As shown in FIGS. 1 and 3, the wheel dressing apparatus of the present invention includes a main support structure 1 having a dovetailed connection 2 on the framework of a grinding apparatus 2 in which a grinding wheel 3 is mounted for rotation about an axis 4. Suitable means not shown is included for moving the wheel dressing apparatus into and out of operative association with the grinding wheel. The basic mounting of the wheel dressing apparatus and the means for moving it toward and away from the grinding wheel is all conventional and not part of the present invention.

The main support structure 1 includes a fixed support 5 extending parallel to the axis of rotation 4 of the grinding wheel. Slidably mounted on this fixed support is a second support 6. Ball and ball guide assemblies 7 are provided for permitting sliding of the support 6 on the support 5. This sliding movement of the support 6 is in a direction parallel to the axis of rotation of the grinding wheel.

A tool holder 8 is rotatably mounted on the second support 6 by way of a tool holder bracket 9, shaft 10, and ball bearing assemblies 11. A diamond cutter I2 is secured in the lower end of the tool holder and has a working surface or point 13 adapted to engage the peripheral surface of the grinding wheel. The tool holder is mounted for rotation about an axis 14.

In FIG. 2, the peripheral contour of the grinding wheel to be dressed is shown. A first straight section 15 extends from one side of the grinding wheel toward the other while a second curved section 16 in the form of a radius connects the straight section to the other side of the grinding wheel. With this peripheral contour, the cutter, in moving between the two positions shown in FIG. 2, must be cross-fed transversely of the periphery of the wheel while it follows the straight section 15 and must then be moved both transversely and radially while it moves along the section 16. As seen from FIGS. 1 and 2, the axis of rotation 14 of the tool holder is disposed radially inwardly of the periphery of the grinding wheel. Also, the working surface 13 of the diamond cutter is offset from this axis of rotation. Accordingly, simple rotation or pivoting of the tool holder will cause the cutter to move around the radius on the periphery of the grinding wheel while the cutter is maintained normal to this curved surface.

The mechanism for controlling the movement of the cutter along the periphery of the grinding wheel includes a cam-cam follower assembly. More particularly, the support 6 is provided with a slide guide 17 slidably mounting a cam slide 18 for vertical movement. The cam slide is adapted to be reciprocated in the vertical direction by means of a. hydraulic piston and cylinder assembly 19 having the cylinder 20 fixed to the support 6 and a piston rod 21 connected to the cam slide 18.

Cam members are fixed to opposite sides of the cam slide. As viewed in FIG. 1, a cross-feed cam 22 is fixed to the left side of the cam slide for controlling the crossfeeding movement of the cutter while a pivot cam 23 is fixed to the right side of the cam slide for controlling the pivoting movement of the cutter. A cross-feed cam follower 24 cooperates with the cross-feed cam 22 to effect the desired cross-feeding of the cutter. The cross-feed cam follower 24 is secured to the fixed support and extends through an opening 25 in the support 6 and into engagement with the cam surface 26 on the cross-feed cam 22. The relationship between the cam surface 26 and follower 24 is best seen in FIG. 4.

In order to maintain engagement between the follower 24 and surface 26, the support 6 is continuously biased to move in a direction away from the viewer in FIG. 1 or to the right as viewed in FIG. 4. A coiled spring motor 27 is mounted on the support 6 and, as best shown in FIG. 3, includes a tension wire 28 connected by a coupling 29 to the fixed support 1. The spring load of the spring motor 27 is in the direction of the arrow shown in FIG. 3.

The shape of the cam surface 26, as shown in FIG. 4, includes a section Y-Y extending at an angle to the path of movement of the cam slide 18 and a section Y-Y' extending parallel to the path of reciprocation of the slide. With this construction, reciprocation of the slide 18 will cause the entire support 6, with the tool holder and cutter mounted thereon, to move in a crossfeeding direction transversely of the periphery of the grinding wheel; that is, parallel to the axis of rotation 4 of the grinding wheel, as the cam surface Y-Y engages against the follower 24. As the cam surface YY" engages the cam 24, however, no cross-feeding movement of the support 6 and cutter 12 will be produced.

At the same time the cam surface 26 and cam follower 24 are riding against each other, a pivot cam follower 30 is riding along a cam surface 31 on the pivot cam 23. This follower 30 is fixed to a slide 32, in turn, slidably mounted on the support 6 by means of slide guides 33. As seen in FIGS. 1 and 2, the slide 32 is adapted to move along a path extending at right angles to the path of vertical reciprocation of the cam slide 18. The slide 32 is connected by a flexible steel band 34 to a pulley 35, fixed to the shaft on which the tool holder is mounted. A spring motor 36 is also fixed to the shaft 10 above the pulley with its tension wire 37 connected to the support 6 by way of a coupling 38. The spring motor is spring loaded in the direction shown by the arrow in FIG. 2 to urge the shaft 10 in a clockwise direction and, thus, urge the tool to pivot in a clockwise direction about the axis 14.

The spring motor together with the flexible steel band 34 also functions to urge the slide 32 to the right as viewed in FIGS. 3 and 4 and in a direction toward the top of FIG. 2. Thus, the pivot cam follower 30 is continuously biased into engagement with the cam surface 31 of the pivot cam 23.

With the cam surface 31 shaped as shown in FIG. 4, reciprocation of the cam slide to cause relative movement of the pivot cam follower 30 along the section XX will cause no pivoting movement of the cutter. This is so since the section X-X' of the cam surface 31 is parallel to the direction of the reciprocating cam slide 18. When, however, the follower 30 moves along the section X-X" of the cam surface 31, the slide 32 will be caused to move back and forth along the slide guides 33 to cause the cutter to pivot about the axis 14 of the shaft 10. The particular shape of the cam surfaces 26 and 31 as shown in FIG. 4 will dress a grinding wheel which may, for example, be used in precision grinding of the race sections of instrument type bearings. These bearings will have a race surface complementary to the peripheral contour of the grinding wheel.

With the construction of the cross-feed and pivot cams as described above and with the mounting of the cutter for pivoting movement about an axis offset from the working surface of the cutter, the cutter will move smoothly back and forth across both the straight and curved sections of the grinding wheel and the cutter will be maintained, at all times, normal to the surface being dressed. Also, only a single hydraulic drive 19 is needed to properly control all movement of the cutter during the dressing operation.

The particular cross-feed and pivot cams shown in FIG. 4 effect movement of the cutter along the path shown at the top of FIG. 4. By replacing the slide guide 18 with one having different cross-feed and pivot cams, such as shown in FIG. 5-9, the cutter can be caused to move along the paths shown at the top of these figures to dress grinding wheels having these peripheral contours. Such grinding wheels are particularly suited for grinding bearing races of complementary shape.

I claim:

1. A wheel dressing apparatus for dressing the periphery of a grinding wheel supported for rotation about a first axis; said grinding wheel having a predetermined peripheral cross-sectional contour, said apparatus comprising:

a. a tool holder for holding a cutting tool, said holder being mounted for rotation about a second axis lying in a plane extending perpendicular to said first axis;

b. a cutting tool mounted on said holder and having a working surface adapted to engage the periphery of said grinding wheel, said cutting tool extending radially and perpendicular to said second axis for rotation thereabout upon rotation of said tool holder with the working surface thereof offset from said second axis;

c. support means for mounting said tool holder for linear movement along a first path extending parallel to said first axis; and

d. cam and follower means for controlling rotative and linear movement of said tool holder to cause the working surface of said cutting tool to follow the peripheral cross-sectional contour of said grinding wheel as the grinding wheel is rotated about said first axis.

2. A wheel dressing apparatus according to claim I wherein:

a. said support means includes:

1. a first fixed support, and

2. a second support mounted on said first support for linear movement along said first path, said tool holder being rotatably mounted on said second support.

3. A wheel dressing apparatus according to claim 2 wherein:

a. said cam and follower means includes:

1. a first cam mounted on said second support for movement along a second path,

2. a first follower fixed to said first support and cooperating with said first cam to produce sliding of said second support along said first path upon relative movement of said first follower and first cam,

3. a second cam mounted on said second support for movement along a third path, and

4. a second follower operatively connected to said tool holder and cooperating with said second cam to produce rotative movement of said tool holder upon relative movement of said second follower and second cam.

4. A wheel dressing apparatus for dressing the periphery of a grinding wheel supported for rotation about a first axis; said grinding wheel having a predetermined peripheral cross-sectional contour, said apparatus comprising:

a. a first fixed support;

b. a second support slidably mounted on said first support for linear movement along a first predetermined path, parallel to the axis of rotation of the grinding wheel;

c. a first slide mounted on said second support for movement along a second predetermined path;

d. a second slide mounted on said second support for movement along a third predetermined path;

e. a tool holder rotatably mounted on said second support for rotation about a second axis extending perpendicular to said first axis;

f. means connecting said second slide to said tool holder for rotating said tool holder upon sliding movement of said second slide;

g. a cutting tool mounted on said tool holder and extending radially toward the axis of rotation of said tool holder with the working surface of the tool offset from said axis of rotation;

h. cam means secured to said first slide for movement therewith;

i. a first follower fixed to said first support for cooperating with said cam means to produce sliding of said second support along said first predetermined path upon relative movement of said first follower and said cam means; and

j. a second follower fixed to said second slide for cooperating with said cam means to produce sliding movement of said second slide upon relative movement between said second follower and said cam means.

5. A wheel dressing apparatus according to claim 4 wherein:

a. the axis of rotation of the tool holder is disposed radially inwardly of the peripheral contour of the grinding wheel by a small fraction of the radius of the grinding wheel; and

b. the cutting tool extends radially of the axis of rotation of the grinding wheel.

6. A wheel dressing apparatus according to claim 5 wherein:

a. said cam means includes:

1. a first cam cooperating with said first follower,

and

2. a second cam cooperating with said second follower.

7. A wheel dressing apparatus according to claim 6 further including:

a. power means for reciprocating said first slide along said second path;

b. first biasing means urging said second support in one direction along said first predetermined path and said first cam into engagement with said first follower, said first cam having a first cam surface extending along said second path and facing in said one direction along said first predetermined path; and

c. second biasing means urging said second slide along said second path in the same direction as said second support is urged and said second follower into engagement with said second cam, said second cam having a second cam surface extending along said second path and facing in an opposite direction to that of said first cam surface.

8. A wheel dressing apparatus according to claim 7 wherein:

a. said second biasing means includes:

l. spring means connected to said tool holder and urging it in one direction of rotation; and

2. means connecting said spring means to said second slide for urging the second slide in the same direction as said second support.

'gg gg UNITED STATES PATENT OFFICE @ERTIFICATE OF CORRECTION Dted Afigust 6, 1974 *Pmzent No. 3,827,420

Invenfiofls) Nils O. Hoglund It is certified that error appears in the .abcwe-ddentified patent enfi that said Letters Patent are hereby corrected as shown below:

- Colfimn 1, line 42, "U.S. Pat. 'Nos," should read --patents numbered-=-.

Column 3, line 29, "Y-Y'" should read -YY".

Signed and sealed this 5th day of November 1974.

(SEAL) Attest:

. MCCOY M. GIBSON JR c. MARSHALL DANN Attesting Officer 4 Commissioner of Patents 

1. A wheel dressing apparatus for dressing the periphery of a grinding wheel supported for rotation about a first axis; said grinding wheel having a predetermined peripheral cross-sectional contour, said apparatus comprising: a. a tool holder for holding a cutting tool, said holder being mounted for rotation about a second axis lying in a plane extending perpendicular to said first axis; b. a cutting tool mounted on said holder and having a working surface adapted to engage the periphery of said grinding wheel, said cutting tool extending radially and perpendicular to said second axis for rotation thereabout upon rotation of said tool holder with the working surface thereof offset from said second axis; c. support means for mounting said tool holder for linear movement along a first path extending parallel to said first axis; and d. cam and follower means for controlling rotative and linear movement of said tool holder to cause the working surface of said cutting tool to follow the peripheral cross-sectional contour of said grinding wheel as the grinding wheel is rotated about said first axis.
 2. means connecting said spring means to said second slide for urging the second slide in the same direction as said second support.
 2. A wheel dressing apparatus according to claim 1 wherein: a. said support means includes:
 2. a second support mounted on said first support for linear movement along said first path, said tool holder being rotatably mounted on said second support.
 2. a second cam cooperating with said second follower.
 2. a first follower fixed to said first support and cooperating with said first cam to produce sliding of said second support along said first path upon relative movement of said first follower and first cam,
 3. a second cam mounted on said second support for movement along a third path, and
 3. A wheel dressing apparatus according to claim 2 wherein: a. said cam and follower means includes:
 4. A wheel dressing apparatus for dressing the periphery of a grinding wheel supported for rotation about a first axis; said grinding wheel having a predetermined peripheral cross-sectional contour, said apparatus comprising: a. a first fixed support; b. a second support slidably mounted on said first support for linear movement along a first predetermined path, parallel to the axis of rotation of the grinding wheel; c. a first slide mounted on said second support for movement along a second predetermined path; d. a second slide mounted on said second support for movement along a third predetermined path; e. a tool holder rotatably mounted on said second support for rotation about a second axis extending perpendicular to said first axis; f. means connecting said second slide to said tool holder for rotating said tool holder upon sliding movement of said second slide; g. a cutting tool mounted on said tool holder and extending radially toward the axis of rotation of said tool holder with the working surface of the toOl offset from said axis of rotation; h. cam means secured to said first slide for movement therewith; i. a first follower fixed to said first support for cooperating with said cam means to produce sliding of said second support along said first predetermined path upon relative movement of said first follower and said cam means; and j. a second follower fixed to said second slide for cooperating with said cam means to produce sliding movement of said second slide upon relative movement between said second follower and said cam means.
 4. a second follower operatively connected to said tool holder and cooperating with said second cam to produce rotative movement of said tool holder upon relative movement of said second follower and second cam.
 5. A wheel dressing apparatus according to claim 4 wherein: a. the axis of rotation of the tool holder is disposed radially inwardly of the peripheral contour of the grinding wheel by a small fraction of the radius of the grinding wheel; and b. the cutting tool extends radially of the axis of rotation of the grinding wheel.
 6. A wheel dressing apparatus according to claim 5 wherein: a. said cam means includes:
 7. A wheel dressing apparatus according to claim 6 further including: a. power means for reciprocating said first slide along said second path; b. first biasing means urging said second support in one direction along said first predetermined path and said first cam into engagement with said first follower, said first cam having a first cam surface extending along said second path and facing in said one direction along said first predetermined path; and c. second biasing means urging said second slide along said second path in the same direction as said second support is urged and said second follower into engagement with said second cam, said second cam having a second cam surface extending along said second path and facing in an opposite direction to that of said first cam surface.
 8. A wheel dressing apparatus according to claim 7 wherein: a. said second biasing means includes: 